Politicians have taken hold of the reins of the global warming debate, even if several of them are trying to drive the planet in different directions. A BBC2 television programme tonight will give an intelligent and balanced account of the moral, economic and scientific issues behind the argument.

Before you become engrossed in the latest reports from the Kyoto world climate conference, wait until you have seen the third programme in the excellent BBC2 Scare Stories series, which will be broadcast this evening at 9.25. "Scorching the Earth" provides an enthralling history of the global warming debate, and the interplay between scientists, environmentalists and politicians on the long path to Kyoto. The commentary, delivered with just the right tone of mild scepticism by Francine Stock, preserves its objectivity, while carefully picking a path through a jungle of facts, theories and just plain exaggeration.

"We could face ecological holocaust," says one environmentalist, shortly to be followed by another scientist saying that man's influence on climate change is "very small and indistinguishable from natural variability".

If anything, the programme leans towards the sceptical side, with some excellent historical footage of scientists making fools of themselves with their global cooling theory of the 1970s. The fear then was of a new Ice Age, and we had some eminent scientists warning us of the danger of burning fossil fuels because of the "Volcano Effect" - the creation of a dust cloud that could blot out some of the sun's energy and cause a fatal chill to the northern hemisphere.

In the 1980s, the Swedish scientist Bert Bolin became the first to identify the "greenhouse effect" and warn that the same action of fuel-burning could lead not to freezing, but to over-heating. But by then we were all suffering from doom-fatigue. How could we be expected to take seriously all these threats of global disaster if the doom-mongers could change their minds so dramatically?

The discovery of the hole in the ozone layer in 1985, however, brought about a big change in perception. Here was a massive change in our environment that had almost certainly been brought about by human intervention. We had made ourselves more susceptible to skin cancer, cataracts and general resistance to disease by squirting CFCs at the very bit of the atmosphere that had been protecting us from the sun's ultraviolet rays. Shortly after the ozone shock came a massive drought in the food-producing region of the mid-west of the United States in 1988.

In that same year, climate became a major issue in the election campaign between George Bush and Michael Dukakis. The Intergovernmental Panel on Climate Change (IPCC) was set up, and politicians took up the argument of the environmentalists. The problem was, however, that the power of the oil and automobile lobbies made a tax on fossil fuels politically unacceptable. The governments of the world had to be seen to be taking greater responsibility over preserving the environment, but ideally without actually doing very much to change the consumption of energy, which was the basic fuel of economic life. In 1990, the IPCC reported that the environment is in danger of changing faster than we can cope with it, and faster than it can adapt to cope itself. In 1995, their report on Climate Change went one crucial step further, saying that humanity is having an adverse effect on the climate. Then came the backlash, with scientists being employed by the oil industry to discredit the work of members of the IPCC.

The programme concludes that the campaign to reduce gas emissions is "driven by passionate belief more than scientific fact". Yet as one activist says: "In the face of scientific uncertainty, inaction is not neutral." Watch the programme and make up your own mind.